The present invention relates to a rotor for a canned motor of a wet-running centrifugal pump, according to the features specified in the preamble of the independent claim(s) of the present application.
Wet-running centrifugal pumps are applied in their millions as circulation pumps, for example in heating installations for the circulation of heating water (heating circulation pumps) for circulating utility water (circulation pumps) or in another manner for conveying fluids. It is particularly for pumps of a smaller and medium construction size, which were typically earlier driven by asynchronous motors that one nowadays tends to provide these with permanent magnet motors. Thereby, the permanent magnet or magnets arranged in the rotor must be reliably encapsulated in a fluid-tight manner, since with wet-running centrifugal pumps the motor is surrounded by a fluid, for example water. With known designs, this is typically effected such that the rotor comprises a central shaft which in the region of the stator is surrounded by permanent magnets which are encapsulated in a fluid-tight manner by way of a casing formed of stainless steel. The casing at its seam locations and at the connection location is welded to the shaft, which not only requires effort with regard to manufacturing technology, but could also lead to imbalances, which is disadvantageous, in particular for rotors which are envisaged for higher rotation speeds, as is the case with modern pumps controlled by frequency converter.